diff options
Diffstat (limited to 'lib/wavpack/bits.c')
| -rw-r--r-- | lib/wavpack/bits.c | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/lib/wavpack/bits.c b/lib/wavpack/bits.c new file mode 100644 index 00000000..d69cd288 --- /dev/null +++ b/lib/wavpack/bits.c @@ -0,0 +1,141 @@ +////////////////////////////////////////////////////////////////////////////
+// **** WAVPACK **** //
+// Hybrid Lossless Wavefile Compressor //
+// Copyright (c) 1998 - 2006 Conifer Software. //
+// All Rights Reserved. //
+// Distributed under the BSD Software License (see license.txt) //
+////////////////////////////////////////////////////////////////////////////
+
+// bits.c
+
+// This module provides utilities to support the BitStream structure which is
+// used to read and write all WavPack audio data streams. It also contains a
+// wrapper for the stream I/O functions and a set of functions dealing with
+// endian-ness, both for enhancing portability. Finally, a debug wrapper for
+// the malloc() system is provided.
+
+#include "wavpack.h"
+
+#include <string.h>
+#include <ctype.h>
+
+////////////////////////// Bitstream functions ////////////////////////////////
+
+// Open the specified BitStream and associate with the specified buffer.
+
+static void bs_read (Bitstream *bs);
+
+void bs_open_read (Bitstream *bs, uchar *buffer_start, uchar *buffer_end, read_stream file, void *user_data, uint32_t file_bytes)
+{
+ CLEAR (*bs);
+ bs->buf = buffer_start;
+ bs->end = buffer_end;
+
+ if (file) {
+ bs->ptr = bs->end - 1;
+ bs->file_bytes = file_bytes;
+ bs->file = file;
+ bs->user_data = user_data;
+ }
+ else
+ bs->ptr = bs->buf - 1;
+
+ bs->wrap = bs_read;
+}
+
+// This function is only called from the getbit() and getbits() macros when
+// the BitStream has been exhausted and more data is required. Sinve these
+// bistreams no longer access files, this function simple sets an error and
+// resets the buffer.
+
+static void bs_read (Bitstream *bs)
+{
+ if (bs->file && bs->file_bytes) {
+ uint32_t bytes_read, bytes_to_read = bs->end - bs->buf;
+
+ if (bytes_to_read > bs->file_bytes)
+ bytes_to_read = bs->file_bytes;
+
+ bytes_read = bs->file (bs->user_data, bs->buf, bytes_to_read);
+
+ if (bytes_read) {
+ bs->end = bs->buf + bytes_read;
+ bs->file_bytes -= bytes_read;
+ }
+ else {
+ memset (bs->buf, -1, bs->end - bs->buf);
+ bs->error = 1;
+ }
+ }
+ else
+ bs->error = 1;
+
+ if (bs->error)
+ memset (bs->buf, -1, bs->end - bs->buf);
+
+ bs->ptr = bs->buf;
+}
+
+/////////////////////// Endian Correction Routines ////////////////////////////
+
+void little_endian_to_native (void *data, char *format)
+{
+ uchar *cp = (uchar *) data;
+ int32_t temp;
+
+ while (*format) {
+ switch (*format) {
+ case 'L':
+ temp = cp [0] + ((int32_t) cp [1] << 8) + ((int32_t) cp [2] << 16) + ((int32_t) cp [3] << 24);
+ * (int32_t *) cp = temp;
+ cp += 4;
+ break;
+
+ case 'S':
+ temp = cp [0] + (cp [1] << 8);
+ * (short *) cp = (short) temp;
+ cp += 2;
+ break;
+
+ default:
+ if (isdigit ((unsigned char) *format))
+ cp += *format - '0';
+
+ break;
+ }
+
+ format++;
+ }
+}
+
+void native_to_little_endian (void *data, char *format)
+{
+ uchar *cp = (uchar *) data;
+ int32_t temp;
+
+ while (*format) {
+ switch (*format) {
+ case 'L':
+ temp = * (int32_t *) cp;
+ *cp++ = (uchar) temp;
+ *cp++ = (uchar) (temp >> 8);
+ *cp++ = (uchar) (temp >> 16);
+ *cp++ = (uchar) (temp >> 24);
+ break;
+
+ case 'S':
+ temp = * (short *) cp;
+ *cp++ = (uchar) temp;
+ *cp++ = (uchar) (temp >> 8);
+ break;
+
+ default:
+ if (isdigit ((unsigned char) *format))
+ cp += *format - '0';
+
+ break;
+ }
+
+ format++;
+ }
+}
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